Conjugated alkadienes can be polymerized in various ways. For some applications the polyalkadienes should have a high content of cis-configurations in the polymer. The high cis-polybutadiene, for example, is very resilient. For other purposes a polymer with high content of transconfigurations is preferred. High trans-polyisoprene, for instance, is a resinous, nonresilient, elastic, thermoplastic, tough, crystalline, solid polymer. These high trans-polyalkadienes can be used for electrical insulation of wires and cables, for the production of battery casings and golf ball covers.